This invention relates generally to electrical connectors, and more specifically, to electrical connectors having contacts arranged in a staggered pattern.
Due to increases in data transmission rates in telecommunications systems, crosstalk has become a significant problem. Crosstalk may be defined as energy which is coupled from one signal line onto a nearby signal line by either capacitive or inductive coupling. This crosstalk results in signal noise which interferes with the purity of the signal being transmitted.
A commonly used telecommunications wiring system is twisted pair wiring wherein pairs of wires are twisted about each other. The wires in a twisted pair carry differential signals and are thus known as signal pairs. Each of the wires in a signal pair carries an equal but opposite signal; that is, the wires carry signals of the same magnitude which are respectively positive and negative. Since these signals are equal but opposite, they generate fields that are equal but opposite. In a twisted pair these equal and opposite fields cancel each other. Thus, minimal crosstalk can occur between one twisted pair and a nearby twisted pair.
Crosstalk in twisted pair wiring systems primarily arises in the electrical connectors which provide an interface between successive runs of cable in a system or an interface with equipment. One source of the crosstalk is the interface between modular plugs and jacks in the telecommunications system. These connectors have terminals or contacts which are spaced closely together and parallel to each other, and this close and parallel arrangement is conducive to crosstalk between nearby lines in different ones of the signal pairs. Further, the terminals in a modular plug are dedicated to specific ones of the twisted wires according to a known industry standard such as Electronics Industries Alliance/Telecommunications Industry Association (“EIA/TIA”)-568. Therefore, ends of the wires must be arranged in a closely spaced parallel sequence in the plug, and these parallel ends are also conducive to crosstalk.
Since crosstalk increases logarithmically as the frequency of the signal increases, the constant trend toward higher data transmission rates has resulted in a need for crosstalk reduction. For example, crosstalk which occurs in a modular jack of a communications cable rises significantly at very high frequencies on the order of 250-500 MHz. Prior art techniques for reducing crosstalk have focused primarily on the modular jacks and on the circuit boards of the modular jacks. For example, the circuit boards provide compensation by routing traces in a predetermined pattern to compensate for the crosstalk between the terminals. However, a delay exists between the source of the crosstalk and the compensation for the crosstalk due to the distance between the mating interface and the circuit board. As such, a need exists for a connector that provides compensation for crosstalk at or near the source of the crosstalk (e.g. the mating plug) and minimizes the creation of additional crosstalk within the jack contacts, thus reducing the overall crosstalk of the connector and increasing the electrical performance of the connector.